BBS: TELESC.NET.BR Assunto: HVYSNOW: Probabilistic Heavy Snow And Icing Discussion De: COD Weather Processor Data: Mon, 16 Mar 2026 07:04:21 +0000 ----------------------------------------------------------- FOUS11 KWBC 160704 QPFHSD Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 304 AM EDT Mon Mar 16 2026 Valid 12Z Mon Mar 16 2026 - 12Z Thu Mar 19 2026 ...Upper Midwest through the Great Lakes...=20 Days 1-3... ...Historic blizzard continues today... The historic blizzard which has been plaguing the Northern Plains and Upper Midwest will continue in earnest today across the Great Lakes. The strong surface low driving this impressive event will steadily advect northeast today after a brief stall this morning over Michigan during occlusion, leading to continued heavy snow from northern IL through the U.P. of MI. The low is expected to pull away well into Canada by 12Z/Tuesday, bringing a slow end to the blizzard. The heaviest additional snowfall is expected from southern WI through the U.P. of MI where snowfall rates above 1"/hr may (60-80% chance) continue through evening, with the heaviest snowfall expected in the higher terrain of the U.P. near the Huron Mountains. The most widespread heavy synoptic snow will wane after 00Z/Tuesday, but before this occurs, the combination of these=20 intense snowfall rates and gusty winds of up to 50 mph will continue blizzard conditions. The heaviest snowfall swath D1 is=20 likely within the impressive deformation axis which will be pivoting west of the surface low as it lifts north, and this deformation is progged to dig as far south as IL/IA Monday morning. This will bring periods of heavy snow and gusty winds with near- blizzard conditions even south of the heaviest snow. However, WPC probabilities indicate the heaviest snow is likely for northern WI, including the Door Peninsula, into the U.P. of MI where they reach 50-90% for an additional 6+ inches of snow today, with locally more than 12 inches possible across the U.P. thanks to lake effect snow contribution (more on that below). The ongoing key messages for this historic blizzard remain, and are linked below (Key Message 1). As the low pulls away late D1 into D2, the heavy synoptic snow will draw to an end, but impressive NW winds and CAA in its wake will bring a period of widespread lake effect snow (LES) to the Great=20 Lakes. Although the lake temperatures are cold, below +5C, and=20 there is considerable ice cover according to GLERL, 850mb temps=20 crashing to around -20C will create steep lapse rates and=20 impressive inversion heights with pronounced omega into the near-=20 surface DGZ. This should be more than sufficient to support heavy=20 LES, with rates above 1"/hr (30-60% chance). While the duration of heavy LES may be somewhat limited as winds begin to weaken and veer as the low pulls away, there is sufficient time for locally heavy accumulations in the favored NW snow belts. WPC probabilities for LES are high D1 (>70%) for 4+ inches in the NW L.P. of MI near Traverse City, the far SW portions of the L.P. of MI, and greater than 50% along the Chautauqua Ridge and the Tug Hill Plateau. LES wanes in coverage D2 but persists heavily east of Lake Ontario where probabilities remain elevated (50-90%) for an additional 4+ inches through Tuesday night. ...Central Appalachians & Mid-Atlantic states... Days 1-2... The strong low pressure /blizzard/ over the Great Lakes will steadily move northeast into Canada today, while the parent upper trough amplifies into the Tennessee Valley and takes on a negative tilt. This will push a powerful arctic cold front eastward across the Ohio Valley, Central Appalachians, and Mid-Atlantic states today. As this front races east, temperatures will plummet on strong CAA, while mid and upper level flow remains southerly in response to the strongly tilted and digging upper trough. This will likely result in precipitation changing over to snow before ending in most areas.=20 While most of this snow will just be conversational, in the colder climates of the higher elevations of the Central Appalachians, this may result in a two-pronged event consisting of heavy snow. The first will be directly behind the front as p-type changes rapidly from rain to snow, leading to a brief period of snowfall rates exceeding 1"/hr (40-60% chance) from the Central Appalachians=20 through the Laurel Highlands and into the Finger Lakes region of=20 NY. During this time, however, snowfall accumulations will be=20 modest at just a few inches at most. However, in the wake of this=20 front, the increasing CAA on NW flow will drive potent upslope=20 ascent into the Central Appalachians Monday night through Tuesday=20 aftn. Although the column is dry aloft, the DGZ will lower to near=20 the surface, leading to favorable ascent due to the upslope to=20 maximize snow growth. This should cause accumulating snowfall in=20 the higher elevations of WV, where WPC probabilities peak above 50% for 6+ inches of snowfall. Finally, as the trailing vorticity maxima and secondary shortwave embedded within the trough finally kicks east Tuesday aftn/eve, convective snow showers and isolated snow squalls could develop=20 across this area. Additional snowfall accumulations will be light=20 with any of these convective elements, but briefly heavy snow rates and gusty winds could cause local travel impacts. Weiss ...Winter Storm Key Messages are in effect. Please see current=20 Key Messages below... https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!-YEUl4DZ-_f4nBc_zlclvHZTEy2Prhp8OA7kp4NGWeHQ-= gEPJE_lo4KVd8ZWt9WZjMW1K3N4Q5A2j5ulJY71QtZO72E$=20 $$ =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: Capitol City Online (1:2320/107) ----------------------------------------------------------- [Voltar]